Twitter authentication failure with Tweepy

[HSB]

I have dug deeper into this and enabled debug output in Tweepy. But still I am puzzled.

On my MAC (OK)

send: b'GET /1.1/account/verify_credentials.json HTTP/1.1\r\nAccept-Encoding: identity\r\nHost: api.twitter.com\r\nAuthorization: OAuth oauth_nonce="82970471272089437891549199975", oauth_timestamp="1549199975", oauth_version="1.0", oauth_signature_method="HMAC-SHA1", oauth_consumer_key="<key>", oauth_token="<token>", oauth_signature="Rcq0xG7b1icM4WOuWqFG9HkXm4s%3D"\r\n\r\n'
reply: 'HTTP/1.1 200 OK\r\n'

On my NAS (not OK)

send: b'GET /1.1/account/verify_credentials.json HTTP/1.1\r\nAccept-Encoding: identity\r\nHost: api.twitter.com\r\nAuthorization: OAuth oauth_nonce="182485988168612436021549199916", oauth_timestamp="1549199916", oauth_version="1.0", oauth_signature_method="HMAC-SHA1", oauth_consumer_key="<key>", oauth_token="<token>", oauth_signature="w%2F.nkkBk8Ic5kfvfDhM94%2F.cj4qq8%3D."\r\n\r\n'
reply: 'HTTP/1.1 401 Authorization Required\r\n'

The difference between both requests are nonce, timestamp and signature. But that looks natural to me.